MICROBIAL DISEASES OF THE DIGESTIVE SYSTEM

MOUTH Over 300 types of bacteria Dental caries Periodontal disease –Gingivitis –Periodontitis

DENTAL CARIES Dental plaque –Accumulation of microorganisms and their products (dental plaque) –Streptococcus mutans –Actinomyces spp.

DENTAL CARIES (cont.) Attachment Colonization Sugar (glucose+fructose) Glucose > dextran Fructose > lactic acid

Enamel

DENTAL CARIES (cont.) Lactic acid softens enamel Initial, S. mutans Advance, Lactobacillus spp. Pulp infection

DENTAL CARIES (cont.) Treatment –Root canal therapy –Penicillin Prevention –Fluoride –Reduced sucrose in diet –Brushing and flossing –Professional cleaning

PERIODONTAL DISEASE Inflammation of teeth-supporting tissue Gingivitis –Gums inflammation (bleeding)

PERIODONTAL DISEASE (cont.) Streptococci, actinomyces and gram-negative bacteria Prevented by brushing & flossing

PERIODONTITIS Chronic gingivitis 10% of teeth loss Affects bone Surgery and cleaning

LOWER DIGESTIVE SYSTEM Infections –Salmonellosis Intoxications –Staphylococcus aureus

Practice that contributed to food- borne disease ( ) 1. Improper holding temperature 2. Poor personal hygiene of food handlers 3. Food obtained from an unsafe source was the least commonly reported factor

Syndrome A group of symptoms that together are characteristic of a specific disease

Gastrointestinal Syndrome Gastroenteritis associated with nausea, vomiting and diarrhea

Dysentery syndrome Any infectious disease of the large intestine marked by ulceration, hemorrhagic diarrhea with mucus and often blood

GASTROENTERITIS Inflammation of the stomach and intestinal mucosa

GASTROENTERITIS (cont.) Abdominal cramps Nausea Vomiting Dehydration

GASTROENTERITIS (cont.) E. coli Shigella spp. Salmonella spp. Campylobacter spp. Staphylococcus aureus Rotavirus Norwalk virus (Noro virus)

Routes of exposure to enteric pathogens Fecal contamination (human/animal) –Food –Water –Fomites (doorknobs, telephones) –Direct contact

Petting zoos

Non-traditional pets

Pest animals

Population at risk

Occupational risk

STAPHYLOCOCCAL FOOD POISONING S. aureus survives 30 min at 60 o C (140 o F) High salt concentration Skin and nasal mucosa Facultative anaerobes -Coagulase positive

STAPHYLOCOCCAL FOOD POISONING (cont.) Temperature abuse –Food let to cool slowly –Organisms grow producing toxin

STAPHYLOCOCCAL FOOD POISONING (cont.) High risk foods –Custards –Cream pies –Ham

STAPHYLOCOCCAL FOOD POISONING (cont.) Toxin affects brain’s vomiting reflex Abdominal cramps Diarrhea

SALMONELLOSIS

Salmonella spp. Gram negative rods Facultative anaerobe 2000 serovars

SALMONELLOSIS (cont.) S. dublin S. enteritidis S. typhimurium S. cholerasuis

SALMONELLOSIS (cont.) Domestic animals –Poultry –Swine –Cattle –Dogs and cats

SALMONELLOSIS (cont.) Wild animals –Rodents –reptiles –Terrapins (turtles)

SALMONELLOSIS (cont.) Incubation of h Intestinal mucosa Lymphatic and cardiovascular systems

SALMONELLOSIS (cont.) Fever Nausea Abdominal pain Cramps Diarrhea

SALMONELLOSIS (cont.) Mortality among infants and the elderly Many shed Salmonella for 6 months Many animals are chronic carriers

SALMONELLOSIS (cont.) Treatment –Rehydration –Antibiotics prolong carrier state and increase resistance

TYPHOID FEVER Salmonella typhi –Rare in animals! Incubation –2 weeks

TYPHOID FEVER (cont.) High fever (104 o F) Continual headache Constipation more common than diarrhea 10% fatality rate

TYPHOID FEVER (cont.) Many recovered patients become carriers (Typhoid Mary) Obligatory case report in most states and countries Lifelong immunity

TYPHOID FEVER (cont.) Treatment –Cephalosporins –Chloramphenicol –Amoxillin

Shigellosis

SHIGELLOSIS (Bacillary dysentery) Shigella spp. Gram negative facultative anaerobic rod Only infects humans Low infectious dose –Resistant to low stomach pH

SHIGELLOSIS (cont.) S. sonnei – Most common in the USA – Least severe S. dysenteriae –Uncommon in the USA –Most severe

SHIGELLOSIS (cont.) Shiga toxin –Inhibits protein synthesis –Diarrhea with blood and mucus (dysentery)

SHIGELLOSIS (cont.) 20, ,000 cases/year 5 to 15 deaths Treatment –Rehydration –Fluoroquinolones (severe cases)

Cholera

CHOLERA Vibrio cholerae Aquatic organism Gram-negative rod Non-invasive –toxin producing

Cholera epidemic South America million cases 9,600 deaths

CHOLERA (cont.) Enterotoxin Rice-water stools 20 liters of liquid lost/day Occasional outbreaks in Gulf coast (seafood)

CHOLERA (cont.) 50% mortality if untreated 1% mortality if treated –Rehydration –Tetracycline

Vibrio gastroenteritis Vibrio parahaemolyticus Salt water estuaries Resembles cholera Often foodborne (seafood)

E. coli

Escherichia coli gastroenteritis Enterotoxigenic E. coli Enteroinvasive E. coli Enterohemorrhagic E. coli

Enterotoxigenic E. coli Specialized fimbriae –Attachment Not invasive Toxins Severe diarrhea

Enteroinvasive E. coli Specialized fimbriae –Attachment Toxins (cholera-like) Traveler’s diarrhea (?) Penetrate intestinal lining –Shigellosis-like dysentery

Enterohemorrhagic E. coli O157:H7 strain Foodborne (hamburgers, milk, apple cider) Verotoxins (colon bleeding)

Enterohemorrhagic E. coli (cont.) Cattle carrier Hemolytic uremic syndrome –Blood in urine –Kidney failure

Campylobacter jejuni gastroenteritis Gram-negative microaerophilic spirally curved rods Common in (healthy) domestic animals –May be shed in milk Small infectious dose Dysentery

Yersinia spp. gastroenteritis Common in domestic animals Grows at refrigeration temperature Acute pain

Clostridium perfringens gastroenteritis Gram-positive, spore-forming anaerobic rod Contaminated-cooked meat Temperature abuse Mild diarrhea

Bacillus cereus gastroenteritis Gram-positive, spore-forming anaerobic rod Common in soil and vegetation Gastroenteritis is similar to Cl. perfringens

VIRAL GASTROENTERITIS

ROTAVIRUS Most common viral gastroenteritis 1,000,000 cases/year (USA) 100 deaths/hour (developing countries)

NORWALK VIRUS Common among adults More resistant to chlorine than other viruses No animal models or cell culture available